lftp is a sophisticated command line based file transfer program. Supported protocols include FTP, HTTP, SFTP, and FISH. It has a multithreaded design allowing you to issue and execute multiple commands simultaneously or in the background. It also features mirroring capabilities and will reconnect and continue transfers in the event of a disconnection. Also, if you quit the program while transfers are still in progress, it will switch to nohup mode and finish the transfers in the background. Additional protocols supported: FTP over HTTP proxy, HTTPS and FTP over SSL, BitTorrent protocol. IPv6 is fully supported. There are lots of tunable parameters, including rate limitation, number of connections limitation and more.

aria2 is a utility for downloading files. The supported protocols are HTTP(S), FTP, BitTorrent, and Metalink. It has a powerful segmented downloading ability, downloading a file from multiple sources and multiple protocols and utilizing your download bandwidth to the maximum. It supports downloading a file from HTTP(S)/FTP and BitTorrent at the same time, while the data downloaded from HTTP(S)/FTP is uploaded to the BitTorrent swarm. Using Metalink's chunk checksums, aria2 automatically validates chunks of data
while downloading a file like BitTorrent.

transmission-remote-dotnet is a Windows remote client to the RPC interface of transmission-daemon, which is part of the Transmission BitTorrent client. The application is very much like µTorrent in appearance, and currently supports almost all of the RPC specification.

TurnKey Torrent Server Appliance is a file server appliance with integrated multi-protocol file sharing that can be used to handle all types of file downloads. Files can be added to the download list using the Torrent Server handler extension for Firefox or through a simple Web interface that allows you to manage the server remotely. It is especially useful for centralizing file sharing on a shared network. Anti-virus scanning is included.

Btpd is a utility for sharing files over the BitTorrent network protocol. It runs in daemon mode, thus needing no controlling terminal or GUI. Instead, the daemon is controlled by the btcli command line utility or other programs capable of sending commands and queries on the btpd control socket.